The Tennessee Valley Authority said the Tennessee River has just nine-tenths of an inch of rain runoff for the month of October, the lowest level ever recorded for the watershed.
TVA officials said February was East Tennessee's last month of normal runoff amounts this year.
"It's been a really dry last half of the calendar year," said TVA spokesperson Travis Brickey. "Now in October we're seeing the lowest runoff totals in 142 years of record."
Many TVA waterways have reached winter pool levels earlier than normal this year.
"It's going to take a long rain event, soaking rain, multiple inches of rain all across the Tennessee River Valley as we start building that deficit back up, but it's going to take a lot of rain," Brickey said.
Brickey said TVA still has a large amount of water in storage, but a lot of precipitation is needed to make up the current runoff deficit.
"We really need to break out of this dry spell because it won't be long until we start turning the corner on the year and start looking toward the spring fill," Brickey said. "We've got to make up this deficit that we're in now plus normal to start getting those up to normal summer pool next year."